Client-side Monitoring
VAC runs in the background while you’re playing a VAC-secured game (like CS:GO or TF2). It monitors for known cheats, suspicious behavior, and unauthorized modifications to game files or memory.
Signature Detection
VAC uses a signature-based system, similar to antivirus software. It maintains a database of known cheat signatures (patterns of code). When a match is found in the game’s memory or files, the system flags it.
Heuristic & Behavioral Analysis
In addition to static signature detection, VAC can use heuristic methods to analyze behavior patterns. This includes detecting how a cheat interacts with the game (e.g., aimbot patterns, wallhacks).
Memory Scanning
VAC scans specific areas of your computer’s memory to detect any injected code or tools manipulating the game. It focuses on areas known to be used by cheats.
Delayed Bans for Obfuscation
To prevent cheat developers from knowing what triggered detection, VAC typically applies bans days or even weeks after the violation. This tactic helps prevent reverse engineering of the detection method.
No Real-Time Banning
VAC is not designed to ban players in real time. Instead, it logs suspicious activity and, after analysis and confirmation, applies bans in waves.
Server Communication
VAC checks are performed both locally and through communication with Valve’s servers. Some server-side checks validate the client’s behavior and detect anomalies.
Obfuscation and Self-Protection
VAC itself is protected against tampering. It uses various methods to hide its presence and resist reverse engineering, making it hard for cheat developers to study how it works.
Steam Account Flagging
Once a cheat is detected and verified, Valve flags the Steam account with a VAC ban. This ban is permanent, non-negotiable, and public.
Shared Ban List
VAC bans apply across all VAC-secured games using the same engine. For example, a VAC ban in CS:GO also affects other Source Engine games.
Privacy Respect
VAC does not search your personal files. It only scans memory and file areas related to the game while it’s running, respecting user privacy as stated in Valve’s policies.
Frequent Updates
Valve regularly updates VAC to improve detection, patch exploits, and add new cheat signatures.